The present invention provides a method and apparatus for filtering an
optical signal. The method includes receiving at least one input optical
signal, forming first and second optical signals using the at least one
input optical signal, and modifying at least one portion of the first
optical signal using a plurality of non-waveguiding electro-optic phase
adjusters. The method also includes forming an output optical signal by
combining the first optical signal, including the at least one modified
portion of the first optical signal, with the second optical signal.